A surgical method was developed to cannulate chronically both the portal and hepatic veins of laboratory rats. This experimental system is useful for studies on intestinal absorption and hepatic extractions of nutrients. With this experimental system, the following objectives can be determined (1) the effect of ethanol on GI absorption and liver metabolism and (2) glucose paradox. In the first study, the rate of ethanol elimination will be determined in rats meal-fed with diet containing glucose, fructose, mixture of glucose and fructose, and sucrose to determine the importance of alcohol dehydrogenase and redox state in liver on the metabolism of ethanol in vivo. In the second study, portal-hepatic difference of glucose and gluconeogenetic precursors will be determined in order to resolve the paradox that liver can not utilize glucose efficiently. Our results, in the latter subject, show that liver can utilize exogenons glucose and can synthesize glycogen directly from exogenous glucose directly. Recent theory on the pathway of glycogen synthesize in liver (Glucose-C3-G6P-Glucogen) was found to be based on questionable data and inadequate method of calculation.